This invention relates to perfume-containing carriers which significantly enhance the substantivity of perfume to laundered fabrics. More particularly, this invention relates to particulate detergent compositions which include as a component thereof a perfume-containing carrier which is able to impart a pleasing perfume fragrance to the finished laundered fabrics with only minimal amounts of perfume.
Perfume substances which modify or enhance the aroma of detergent compositions or impart a pleasing aroma thereto are well-known in the art. U.S. Pat. No. 4,131,555 and 4,228,026, are illustrative of patents which describe substances intended to impart a pleasing aroma or fragrance to liquid and granular detergent compositions. The described methods of preparation consist of mixing the perfume substances, in solid form, with the prepared detergent compositions to form a homogeneous composition. Perfumes which are in liquid form are conventionally added to liquid detergent compositions as a component thereof or sprayed upon the surface of granular detergent compositions. However, detergent compositions which are thus prepared are unable to impart a perfume fragrance to the fabrics being laundered notwithstanding the enhanced aroma of the composition itself. Primarily, this is because the perfume substances in the detergent composition are rapidly dispersed and diluted during laundering in the aqueous wash solution along with the water-soluble components of the detergent composition. Consequently, only a relatively minor amount of the perfume is available to contact and adhere to the fabric being laundered, the major portion of the perfume being drained from the washing machine with the wash solution during the wash cycle. Moreover, to the extent that some perfume is still in contact with the fabric after the washing operation, it tends to be dissipated subsequently during drying, such as, for example, in a gas or electric dryer in which the washed fabrics are tumbled at relatively high temperatures. As a result, fabrics laundered with conventional detergent compositions generally retain only a very faint perfume fragrance which has no particular aesthetic appeal to the user. There is, therefore, a need in the art for an additive to conventional detergent compositions which can effectively provide a perfume fragrance to fabrics being laundered such that the finished laundered fabrics have added appeal to the user.
U.S. Pat. No. 4,259,373 discloses a fabric conditioning article for use in an automatic washer or dryer consisting of a sealed water-in-soluble pouch containing what is described as a softener/antistat composition. In Example II of the patent, there is described a preparation procedure for such antistat composition wherein clay and solid perfume are mixed and the mixture then blended with sprayed particles of certain quaternary ammonium salts. The resulting composition is then filled into a sealed polyester pouch.
Included among the perfume-containing carriers of the invention described herein is a particular embodiment which comprises a perfume, particles of clay and a quaternary ammonium compound (sometimes referred to herein as a "QA" compound for convenience). Compositions containing clay and QA compounds are broadly described in the art relating to fabric softeners and anti-stat compositions. U.S. Pat. No. 3,886,075, for example, describes a composition containing a smectite clay, a water-soluble QA compound and an "amino compatabilizing agent" which is said to provide fabric softening and anti-static effects. U.S. Published Patent Application No. B305,417 describes a granular laundering composition comprising a soap-based granule, a smectite-type clay and a quaternary ammonium anti-static agent. In U.S. Pat. No. 3,862,058, a clay and a quaternary ammonium compound are added to a non-soap synthetic detergent compound to provide a granular laundry detergent composition. U.S. Pat. Nos. 3,993,573 and 3,954,632 describe fabric softening compositions containing the aforementioned clay and QA compounds in combination with a so-called "acid compatibilizing agent". U.S. Pat. No. 4,292,035 discloses a softening composition comprising smectite clay; an amine or quaternary ammonium compound as a softening agent; and an anionic surfactant wherein the fabric softening agent is reacted with the clay to form an "organo-clay complex" prior to the addition of the anionic surfactant.
The methods described in the art for preparing the aforementioned fabric softening compositions are characterized by either a deposition of QA compound upon granules composed of a uniform blend of clay with detergent and other ingredients (rather than a preferential deposition upon clay granules) or alternatively, the QA compound is reacted with the clay to provide a modified clay in which preferably from about 10 to about 60 molar percent of the exchangeable cations are alkyl substituted ammonium ions. Thus, for example, U.S. Pat. Nos. 3,862,058 and 3,886,075 describe a method of preparation whereby the clay is initially admixed in a crutcher with the detergent, builder and other ingredients of the laundering composition and the resulting mixture then spray-dried to form granules. The QA compound is thereafter sprayed upon the granules from a melt, it being a critical aspect of the method of preparation to avoid spraying the detergent granules with an aqueous solution or suspension of the QA compound. United States Published Patent Application B305,417 discloses a method of preparation wherein clay is mixed with soap-based granules in a drum mixer. The QA compound is then added to the resulting composition by spraying from a melt. U.S. Pat. No. 3,594,212 describes a method of softening fibrous materials wherein such materials are successively impregnated with an aqueous dispersion of clay and an aqueous solution of QA compound, the amount of QA compound in solution being sufficient to effect at least a partial cation exchange with the clay retained on the fibrous material. In U.S. Pat. No. 3,948,790 to Speakman, there is described a procedure for preparing "quaternary ammonium clays" whereby a QA compound is reacted with clay by slurrying the untreated clay in a solution containing the desired quantity of QA compound. The QA compounds which may be thus employed are said to be restricted to short-chain compounds having a maximum of four carbon atoms per chain, the total number of carbon atoms in the compound not exceeding eight. The quantity of such QA compound added to the solution is controlled so as to provide the desired degree of ion exchange with the clay. The examples of the patent describe various treated clays in which from about 5 to 40% of the exchangeable cations are replaced by quaternary ammonium cations, the amount of QA compound in solution being necessarily restricted to that which is required to effect a partial exchange reaction with the clay. Accordingly, the prior art does not contemplate the particular combination of clay particle and QA compound employed in the present invention, much less contemplate using such combination as a carrier for perfume in accordance with the invention.